Activity-acidity relationship in zeolite Y Part 2. Determination of the acid strength distribution by temperature programmed desorption of ammonia

In this paper we will have a detailed look at a numerical procedure that allows the estimation of the acid site strength distribution using a single temperature programmed desorption (TPD) experiment. The possibility of estimating these parameters is of paramount importance in the determination of quantitative relationships between activity and acidity. The application of the procedure to a set of simulated thermograms gives a clear view of the applicability of this method. The procedure was tested both in single and multi energy distributions, as well as quasi-continuum distributions. Then the method has been applied on TPD thermograms obtained from catalysts based on two different forms of zeolite Y. In part 3 of this series, the acid site distributions obtained here will be used in an activity-acidity relationship, using a Bronsted type equation, similar to the one used in homogeneous acid catalysis. (C) 1999 Elsevier Science B.V. All rights reserved.